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Abstract
In this study, the existing R.C buildings with different heights and affected by high seismic forces are strengthened using four strengthening techniques. The first and second techniques are based on the Free Spanning Virendel System [P.V Banavalkar]. The third one is developed by adding shear walls to the existing buildings. In the fourth technique, the addition ofbracings ended with Visco-Elastic (VE)-dampers is considered. To simulate the zero-element length connections needed for two of the considered strengthened buildings, a modification to IDARC-version4 program is developed. In evaluating the accuracy of the translational spring, comparisons between the values of the base shear capacity, story drift ratios, and lateral displacements of the examined structural systems obtained from using IDRAC program and those obtained using DRAIN-2DX are made. The study shows that the proposed modification for IDARC program succeeded to model the translational spring element in the horizontal and/or the vertical directions. A comparison between the results of this study and the work done in 1998, in which the computer program DRAIN-2DX is used, shows that the results of the two programs are in a very good agreement. The study concludes that the modification made to the IDARC computer program is a very good tool to simulate the zero-element length connection.
This thesis examines also the limits given by modem international codes of rehabilitation for a performance-based evaluation of strengthened buildings. Structures with different heights of 8, 12, 16, and 20-stories at the condition of nominal deterioration represented by the appropriate hysteretic parameters are considered in this study. The performance evaluation is based on comparing the overall structural damage of both the original and retrofitted buildings. The overall structural damage is represented by the overall damage indices, the maximum inter-story drift ratios, base shear ratios and the overall drift ratios.
Finally, the effect of deterioration conditions represented by appropriate hysteretic properties is examined in accordance with modem codes of rehabilitation. Buildings with different heights of 12, and 16-stories at the conditions of Negligible, Nominal and Severe deterioration condition are considered in this study. The performance evaluation is conducted based on comparisons between the modern codes of rehabilitations limits for collapse prevention level and those obtained from this research.